JP5473098B1 - Stoker-type incinerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stoker-type incinerator capable of burning a combustible material having a high water content such as sludge while reducing the generation of CO without assisting combustion.
SOLUTION: An incinerator main body 2, a dry stalker 3 and a combustion stalker 4 disposed in the incinerator main body 2, and an exhaust gas outlet provided on the ceiling 2a of the incinerator main body 2 above the upstream side of the dry stalker 3. 6 and the lower induction path 7 for guiding the gas generated on the dry stalker 3 between the ceiling 2a of the incinerator body 2 and the dry stalker 3 onto the combustion stalker 4 and the combustion exhaust gas generated on the combustion stalker 4 as exhaust gas And a radiation plate 9 that divides into an upper guide path 8 that leads to the outlet 6 and that radiates heat to the combustible W on the dry stoker 3.
[Selection] Figure 1

Description

  The present invention relates to a stoker-type incinerator suitable for burning high moisture content waste such as sewage sludge and high moisture content such as biomass fuel.

  Conventionally, the shape of the stoker-type incinerator main body is roughly divided from the flow of the combustion gas and the position of the outlet, and as shown in FIG. 4, (a) a convection type in which the flow direction of the waste gas and the flow direction of the combustion gas are opposed to each other, (B) A parallel flow type in which the flow direction of the waste gas and the flow direction of the combustion gas are parallel flows, (c) an AC type in which both flows intersect in an intermediate type between the convection type and the parallel flow type, (d) There are gas flow paths on the upstream side and downstream side of the flow, respectively, and it is classified into a double flow type that combines the characteristics of a convection type and a cocurrent type by a damper function installed in the furnace (Non-patent Document 1).

  The parallel flow type is suitable for high-quality garbage with good ignitability, and the AC type is suitable for large fluctuations in waste quality.

  And in a convection type, since the radiant heat (radiant heat) by combustion gas works effectively on the garbage of a dry zone, it is suitable for burning wastes with high moisture content, such as sewage sludge.

  Sewage sludge has a high moisture content of 70% or more, and in order to burn it in a stoker-type incinerator with a high moisture content, in a convection-type stoker-type incinerator, moisture is evaporated on a dry stoker, and then a combustion stoker Burn on top. As a heat source for drying, radiant heat from the combustion exhaust gas in the combustion stage and heated air supplied from under the stoker are used.

  FIG. 5 is a cross-sectional view of a main part showing a schematic structure of a conventional convection-type stoker-type incinerator. As shown in FIG. 5, the combustible W such as sludge is supplied onto the dry stoker 22 by the pusher 21 in the furnace of the stoker incinerator 20. Thereafter, the fuel is sent from the dry stoker 22 onto the combustion stoker 23 on the downstream side, and combustion is started. In FIG. 5, the post-combustion stage is omitted.

  As shown in FIG. 5, the combustion primary air G is supplied from the lower portions of the stokers 22 and 23, and is used for drying and combustion. Combustion exhaust gas discharged from the combusted material W on the combustion stoker 23 flows in a direction opposite to the flow of dust, and heats the combusted material W such as sludge by radiation / contact heat transfer at the upper part of the dry stoker 22. Pass while.

On the other hand, on the drying stoker 22, in dry, the combustion product W such as sewage sludge, together with water evaporation, unburned gas and combustible gas volatiles often for CO and hydrocarbons (C m _{H n)} is Occur. The generated evaporated water (H ₂ O), unburned gas (CO), and combustible gas (C _m H _n ) are combusted while being mixed with the combustion exhaust gas and the upper part of the dry stoker 22. When the exhaust gas passes over the dry stoker 22, the temperature is lowered because heat is applied to the sludge by radiation and contact heat transfer. Therefore, the combustion exhaust gas has a temperature of 800 ° C. or less at which the unburned gas (CO) and the flammable gas (C _m H _n ) are hardly combusted at the entrance portion of the dry stoker 22 (upstream portion of the dry stoker 22). Even if heated secondary air for combustion G2 is introduced, CO cannot be sufficiently reduced, and the concentration of CO in the exhaust gas at the incinerator exit becomes about 5000 to 6000 ppm as a measured value.

  In order to reduce the generation of CO, which is a harmful gas, and to burn the unburned gas, it is necessary to raise the temperature.

Planning and design guidelines for waste treatment facility maintenance 220, Fig. 3.3.16, August 10, 1999, National Urban Cleaning Council, Waste Research Foundation

  However, if an auxiliary burner is provided to reduce CO, manufacturing costs and fuel costs increase.

  Therefore, the main object of the present invention is to provide a stoker-type incinerator that can burn a combustible material having a high water content such as sludge without increasing the amount of CO generated.

  In order to achieve the above object, a stoker-type incinerator according to the present invention comprises an incinerator body, a dry stoker and a combustion stoker disposed in the incinerator body, and the incinerator above the upstream side of the dry stoker. An exhaust gas outlet provided on the ceiling of the main body, a lower induction path for guiding the gas generated on the dry stoker between the ceiling of the incinerator main body and the dry stoker on the combustion stoker and the combustion stoker And a radiation plate that divides the generated combustion exhaust gas into an upper guide path that guides the generated exhaust gas to the exhaust gas outlet and radiates heat to a combusted object on the dry stoker.

  The radiation plate may be formed of a metal plate if the gas generated from the combusted material does not contain a corrosive component such as chlorine, but if it contains a corrosive component, it is preferably formed of a ceramic plate.

  It is preferable that the radiation plate is detachably supported by a water-cooled tube or an air-cooled tube horizontally installed in the incinerator main body.

  It is preferable that the metal radiating plate is provided with a hook-shaped hook portion for hooking the water-cooled tube or the air-cooled tube on one end side.

  In one aspect, the water-cooled tube or the air-cooled tube that supports the radiation plate is formed of a square tube having a square cross section, and a contact portion that can contact the rear end surface of the radiation plate is erected at an intermediate portion of the upper surface of the square tube. Is done.

  The exhaust gas generated in the incinerator is attracted by the induction fan of the exhaust gas treatment system, is treated in the middle, and is discharged from the chimney. According to the present invention, the evaporated moisture, unburned gas, and combustible gas generated from the high moisture content burned material on the dry stoker, together with the primary combustion air supplied from the lower part of the dry stoker, Under the action of the attraction force by the induction fan, the radiation plate induces it on the combustion stalker, so that it is mixed with the flame actively burning on the combustion stalker and burned. On the combustion stoker, the combustion exhaust gas is not yet deprived of heat, so that a high temperature capable of complete combustion can be maintained. Thereafter, the high-temperature combustion exhaust gas generated on the combustion stoker heats the radiation plate when it is guided by the radiation plate to the exhaust gas outlet of the incinerator main body, and the radiation on the dry stoker is heated by the radiant heat from the heated radiation plate. The combustion product is heated, and the gas generated from the combustion product on the dry stoker is also heated. As a result, it is possible to burn a combustible material having a high water content such as sewage sludge while reducing the generation of CO without performing auxiliary combustion in the secondary combustion chamber.

It is principal part sectional drawing which shows roughly one Embodiment of the stoker type | mold incinerator which concerns on this invention. It is principal part sectional drawing which shows an example of the support structure of the radiation plate which is this invention component. It is principal part sectional drawing which shows the other example of the support structure of the radiation plate which is this invention component. It is sectional drawing which shows the type of the conventional stoker type | mold incinerator. It is sectional drawing which shows an example of the conventional stoker type incinerator.

  An embodiment of a stoker-type incinerator according to the present invention will be described below with reference to FIGS.

  FIG. 1 is a cross-sectional view schematically showing an embodiment of a stoker-type incinerator according to the present invention. As shown in FIG. 1, the stoker-type incinerator 1 includes an incinerator body 2, a dry stoker 3 that dries the combusted material by hot air and radiant heat, and raises a flame to combust the combusted material to 900 ° C. or higher. Combustion stoker 4 that forms a high-temperature region, post-combustion stoker 5 that completely burns unburned components, exhaust gas outlet 6 provided on the ceiling 2a of the incinerator body 2 above the upstream side of the dry stoker 3, and an incinerator body 2, extending between the ceiling 2 a and the dry stalker 3, and guiding the gas generated on the dry stalker 3 to the combustion stalker 4, and the combustion exhaust gas generated on the combustion stalker 4 as the exhaust gas outlet 6. And a radiation plate 9 that radiates heat to the combustible W on the dry stoker 3.

  Further, the incinerator body 2 has a supply port 10 for supplying a combusted material W such as sludge from the top, and a supply pusher 11 for supplying the combusted material W supplied from the supply port 10 into the incinerator body 2. The main ash chute 12 for removing the main ash after combustion of the combustible W from the incinerator is provided.

  The dry stoker 3 is supplied with combustion primary air (hot air) G heated to 200 ° C. or more from the lower wind box 13. Similarly, combustion primary air (hot air) is also supplied to the lower portions of the combustion stoker 4 and the post-combustion stoker 5, respectively.

  An exhaust gas duct 14 is connected to the upper part of the exhaust gas outlet 6, and the exhaust gas duct 14 is connected to a known exhaust gas treatment facility, although not shown. Exhaust gas treatment equipment outside the figure is connected to a dust collector, smoke tower, induction fan, chimney, etc. by ducts (flues) to remove and detoxify the combustion exhaust gas discharged from the stoker incinerator 1 Later, it is released into the atmosphere.

  In the illustrated example, the exhaust gas outlet 6 is provided above the most upstream part of the dry stoker 3. By arranging the exhaust gas outlet 6 at the most upstream part of the dry stoker 3 in this way, the upper guide path 8 is provided longer.

  During the drying of the combustible W such as sludge, the evaporated water, unburned gas and combustible gas, and the primary air for combustion supplied to the drying are attracted by an induction fan not shown in the figure. Guided by the closed radiation plate 9, guided to the combustion stoker 4 through the lower guide path 7, and mixed with the upper part of the flame that is actively burning on the combustion stoker 4. Further, the combustion primary air G supplied to the dry stoker 3 also contributes to the combustion on the combustion stoker 4. On the combustion stoker 4, the combustion exhaust gas has not been deprived of heat yet, so it can maintain a high temperature. The measured value is 900 ° C. or higher, and the temperature at which the unburned gas and the combustible gas can be completely burned. It was.

  Further, the high-temperature combustion exhaust gas generated in the combustion stalker 4 is guided by the radiation plate 9 and guided to the exhaust gas outlet 6 through the upper guide path 8 under the attraction of an induction fan (not shown), and the upper guide path 8 The radiation plate 9 is heated when it passes through. As a result, the combustible W supplied on the dry stoker 3 is supplied from the radiation plate 9 heated by the combustion exhaust gas in addition to the primary air for combustion (hot air) supplied to the dry stoker 3 and the radiant heat from the furnace wall. It is dried by radiant heat.

  Since the radiation plate 9 is made of a material having good heat conductivity, the heat of the high-temperature combustion exhaust gas generated in the combustion stoker 4 is efficiently applied to the combustible W on the dry stoker 3 by heat radiation via the radiation plate 9. And the drying of the combustible W on the drying stoker 3 is promoted.

  The radiation plate 9 can be made of metal if the combustible does not contain corrosive components such as chlorine, but can also be made of ceramic if it contains corrosive components. As the metal radiation plate 9, for example, stainless steel (SUS310S or the like) having a thickness of 4 to 10 mm can be used. As the ceramic radiation plate 9, for example, a SiC plate having a thickness of 10 to 20 mm can be used.

  The radiation plate 9 is supported by a water-cooled tube 15 or an air-cooled tube horizontally installed in the incinerator body 2 and is detachably supported so that it can be easily replaced. By using a water-cooled tube or an air-cooled tube as a support tube for supporting the radiation plate 9, even if these are made of metal, they can withstand long-term use at high temperatures. In the water-cooled tube 15 (or air-cooled tube), cooling water or cooling air flows through the hollow tube.

  As shown in FIG. 2, the metal radiating plate 9 is formed with a hook portion 9a that is bent at one end and is hooked. The hook portion 9a is hooked on a water-cooled tube 15, and the other end is hooked. A pair of water cooling tubes 15 are detachably spanned and supported so as to be placed on the rear water cooling tubes 15. The hook portion 9a may be plate-shaped or pin-shaped, and may be fixed by welding or the like. Moreover, the radiation plate 9 can also be formed of a plurality of radiation plates 9 as shown in FIG.

  As shown in FIG. 3, the water-cooled tube 15A or the air-cooled tube that supports the ceramic radiation plate 9A is formed of a square tube having a square cross section, and the rear end surface of the radiation plate 9 is located in the middle of the upper surface of the square tube. An abutting portion 16 that can abut is erected. The contact portion 16 may be plate-shaped, but may be pin-shaped (not shown). Note that the water-cooled tube 15 or the air-cooled tube having such a configuration can also be used to support the metal radiation plate 9.

  The CO concentration and temperature at the exhaust gas outlet 6 (FIG. 1) were compared between the embodiment of the present invention shown in FIG. 1 (SUS310S having a thickness of 6 mm was used as the radiation plate) and the comparative example without the radiation plate of FIG. In the comparative example, the CO concentration was 6000 ppm or more (the measuring instrument was over the range) and the temperature was about 750 ° C., whereas in the present embodiment, the CO concentration was 10 ppm or less and the temperature was about 750 ° C. It was about 850 ° C. In the embodiment of the present invention, the CO concentration decreased and the temperature increased because the unburned gas and the combustible gas burned.

  The present invention is not construed as being limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Stoker type incinerator 2 Incinerator main body 2a Ceiling 3 Dry stalker 4 Combustion stalker 5 Post combustion stalker 6 Exhaust gas outlet 7 Lower guideway 8 Upper guideway 9, 9A Radiation plate 9a Hook part 15 Water cooling pipe 16 Contact part

Claims (6)

  An incinerator body, a dry stoker and a combustion stalker disposed in the incinerator body, an exhaust gas outlet provided on the ceiling of the incinerator body above the upstream side of the dry stoker, and a ceiling of the incinerator body And the dry stoker are partitioned into a lower guide path that guides the gas generated on the dry stoker onto the combustion stoker and an upper guide path that guides the combustion exhaust gas generated on the combustion stoker to the exhaust gas outlet And a radiating plate that radiates heat to the combusted material on the dry stoker.   The stoker type incinerator according to claim 1, wherein the radiation plate is formed of a metal plate.   The stoker type incinerator according to claim 1, wherein the radiation plate is formed of a ceramic plate.   The stoker-type incinerator according to any one of claims 1 to 3, wherein the radiation plate is detachably supported by a water-cooled tube or an air-cooled tube horizontally installed in the incinerator main body.   The radiation plate is detachably supported by a water-cooled tube or an air-cooled tube installed horizontally in the incinerator main body, and has a bowl-shaped hook portion for hooking the water-cooled tube or the air-cooled tube on one end side. The stoker-type incinerator according to claim 2, wherein the stoker-type incinerator is provided. The water-cooled tube or the air-cooled tube is formed of a square tube having a square cross section, and an abutting portion on which a rear end surface of the radiation plate can abut is provided at an intermediate portion of the upper surface of the square tube. The stoker-type incinerator according to claim 4.

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